Apparatus for dewatering fibrous tubing



Oct. 28, 1958 A. E. H. FAIR APPARATUS FOR DEWATERING FIBROUS TUBING Filed Dec. 12, 1955 3 Sheets-Sheet l Oct. 28, 1958 A. E. H. FAIR APPARATUS FOR DEWATERING FIBROUS TUBING Filed Dec. 12. 1955 3 Sheet et 2 A. E. H. FAIR APPARATUS FOR DEWATERING FIBROUS TUBING Filed D90. 12, 1955 Oct. 28, 1958 3 Sheets-Sheet 3 Mi /j a; M W

United States Patent APPARATUS FOR DEWATERING FIBROUS TUBING Albert E. Harold Fair, Brookline, Mass., assignor to 1gfown Company, Berlin, N. H., a corporation of ame Application December 12, 1955, Serial No. 552,479

3 Claims. (Cl. 92-59) This invention relates to the manufacture of fibrous tubing from wet pulp and pertains more specifically to apparatus for pressing and compacting the tubing, while the fiber is still wet, against a forming mandrel.

Fibrous tubing or pipe such as that commonly employed as soil pipe is made by forming a wet sheet or web of suitable fibers on a cylinder mold, a Fourdrinier wire, or in any other suitable manner, wrapping the wet web about a forming mandrel, drying the web on the mandrel as by heating it in an oven, then stripping the dried tube or pipe from the forming mandrel and impregnating it with a suitable water-repellent or water- 'proofing material such as asphalt, pitch, etc. If desired,

the tube may be stripped from the mandrel before or at any time during drying.

Because of the relatively large amount of water present in the web as his wrapped on the mandrel andthe thickness of the web, the drying step requires prolonged heating at elevated temperatures, the time required be ing of the order of 15 hours or more. This necessitates both a very large oven capacity for given output and also requires a large number of forming mandrels. In addition, the dry tube is highly porous and absorbs a large volume of asphalt, pitch or the like during the impregnating step, leading to high cost of manufacture.

,One object of the present invention is to provide apparatus for pressing and compacting wet fibrous tubing to remove excess water therefrom and reduce the time required for drying.

Another object is to provide apparatus for compacting and densifying fibrous tubing to reduce the amount of waterproofing material subsequently absorbed thereby.

Other and further objects will be apparent from the drawings and from the description which follows.

In the drawings:

Fig. 1 is a plan view of one embodiment of the device of the present invention;

Fig. 2 is an isometric view, partly cut away and in section, showing the wet fibrous tubing in place on the forming mandrel;

Fig. 3 is a view in side elevation of the device shown in Fig. 1;

Fig. 4 is a View in section taken along the line 4-4 of Fig. 3;

Fig. 5 is a plan view, partly broken away and in sec tion, of the perforate pressing face of one of the pressing members;

Fig. 6 is a view in section showing the wet fibrous tubing in place on the mandrel as the pressing operation begins;

Fig. 7 is a view corresponding to Fig. 6 showing the device as the pressing operation is completed,

Fig. 8 is a view in side elevation, partly broken away showing a modification of the device;

Fig. 9 is a view in side elevation of a second embodiment of the invention;

Fig. 10 is a view on an enlarged scale, partly broken ICE away and in section, taken along the line 10- 10 of Fig. 9;

Fig. 11 is aview corresponding to the right-hand portion of Fig. 10 showing the device in open position;

Fig. l2'is a view along the line l212 of Fig. 10

showing the means for locking the device in closed position; and

Fig. 13 is a view corresponding to Fig. 12 showing the device in unlocked position.

tion by means of cross members 18, 18. Auxiliary frame members 14, 14 may be releasably locked in closed position by means of locking pins 20, 20 which extend through mating openings in auxiliary frames 14, 14 and yokes 22, 22 secured to main frames 10, 10. Main frame members 10, 10 and auxiliary frame members 14, 14 together define opposed apertures 15, 15 of suitable size to permit passage therethrough of the fibrous tubing which is to be pressed. Mounted on each of cross members 12, 13, 18 is a hydraulic cylinder 24, 26, 28 provided with pistons 30, 32, 34 carrying on their ends arcuate. pressing segments 36, 38, 40 which when in closed position, as shown in Fig. 7, are in mating engagement, forming together a hollow cylindrical chamber in alignment with apertures 15, 15 and of the proper size to embrace the layer of wet fibrous tubing 44 on its imperforate cylindrical forming mandrel 46. The mating margins 47 of the pressing segments extend parallel to the longitudinal axis of cylindrical forming mandrel 46 when the latter is in position within the chamber formed by' the pressing segments. The inner diameter of the hollow chamber formed by the pressing segments when in mating relation isapproximately equal to the desired ultimate outer diameter of the fibrous tubing.

Each of the pressing segments 36, 38, 40, as shown best in Figs. 4 and 5, includes a hollow supporting member 50. and a plurality of spaced parallel supporting ribs 52, 52 serving to support a perforated metal facing plate 54 which acts as the inner -or pressing face of the pressing segment. The apertures 53 between ribs 52, 52 serve as spaced parallel drain channels extending along the inner face of the pressing segment and communicating with a drain or outlet 56 (see Fig. 4) which is connected by means of flexible tubing 58, 58 (Fig. 3) to a main drain 60. In addition, hydraulicfluid is supplied to each of the hydraulic cylinders through pressure lines 62, 64, 66

from a common pressure source or line 69. Cylinder 28 which is mounted-on auxiliary frames 14 is connected to the pressureline by means of flexible tubing 68. Ten sion springs 70, 72, 74 are secured respectively between pressingsegments 36, 38, 40 and cross members 12, 13,

.1 8 to withdraw the pressing segments from mating engagement when the hydraulic pressure is released. The device preferably includes at leastthree pressing segments of identical size symmetrically arranged about the axis of the mandrel and tubing; if desired, however, the segments may vary in size and any convenient number of .them may be employed.

members 14, 14 may be opened to the position shown in dotted lines in Fig. 3 to admit tubing 44 on mandrel 46 to the pressing segments. Hydraulic fluid under pressure is then supplied to the three cylinders, causing segments 36, 38, 40 to advance from the .position shown in Fig. 6 to the position shown in Fig. 7, expressing water from the fibrous layer 44 through perforate plates 54- into the hollow body portion of each pressing segment, thence through drains to outlet 60. The hydraulic fluidpressure is then released, permitting the pressing segments 'to be retracted by tension springs 70, 72, 74 to their original position. The mandrel together with the pressed fibrous tubing may then be withdrawn from the device and fur- .ther dried in a conventional oven. If the tubing on its mandrel is longer than the length of the pressing segments, the pressing operation may be repeated any required number of times along the length of the tubing to ensure that the entire length of tubing is densified and compacted before it is transferred to a conventional drying oven.

Inasmuch as the inner perforate faces of each of the three pressing segments 36, 38, 40 are of approximately the same area and since the hydraulic fluid pressure is supplied to all three hydraulic cylinders from a common pressure source, the pressure applied to the tubing by all three pressing segments is the same, ensuring uniformity of wall structure in the finished tubing.

In operation of the device as described above, it is found that the finished tubing displays longitudinal ridges on its outer face corresponding to the joints between respective pressing segments 36, 38, 40 because of the fact that a portion of the fibrous mass is squeezed outwardly into the gap between adjacent pressing segments as they advance toward each other and toward the mandrel. In cases where such ridges or ribs are objectionable, they c'an be eliminated by securing a strip of screen wire 80, 80 to the'margin of each pressing segment, as shown in Fig. 8, by soldering or any other suitable manner. Each strip of screen wire projects suificiently beyond the margin of its respective pressing segment so that it overlaps the adjoining pressing segment and slides over the inner surface thereof as the segments are advanced toward the mandrel into mating engagement.

In the embodiment shown in Figs. 9 to 13 inclusive, there is provided a main frame 100 supported by legs 102, 102 and having auxiliary cross bars 104, 104. Rigidly secured on main frame 100 as by bolts 106, 106 are bracket frames 108, 108 which support an elongated housing 110 of generally U-shaped cross-sectional configuration having inturned marginal flanges 112, 112. Mounted in housing 110 for vertical sliding movement is an elongated pressing segment 114 having outwardly extending shoulders 116, 116 which engage flanges 112, 112. An inflatable bladder 118 of resilient, rubber-like material is disposed within housing 110 and is connected by means of air hose 120 to a suitable source of compressed air. Pressing segment 114 is provided with an arcuate perforated pressing face 122 and drain 123 generally similar to that shown in Figs. 4 and 5. Coil springs 124, 124 disposed between flanges 112 and shoulders 116 serve to urge pressing segment 114 to its retracted position. Fixedly mounted on bracket frames 108 adjacent each margin of pressing face 122 is a pair of supporting members 126, 126 of generally wedge shaped cross-sectional configuration, the lateral margins of pressing face 122 sliding along the converging lateral faces of the supporting members from the retracted position shown in Fig. 11 to a fully inwardly extended position in which they are adjacent the forward edges of the supporting members as shown in Fig. 10.

Pivotally mounted on bracket frames 108 at opposite sides thereof are auxiliary brackets or subframes 128, 130, each of which carries a pressing assembly including -a housing 110, pressing segment 114, and bladder 118 identical with that mounted on bracket "frame 108, as

shown best in Fig. 10. In addition, as shown in Fig. 11, bracket 130 carries a third wedge shaped supporting member 132 which is equidistant from and parallel to holding members 126, 126 and adjacent the lateral margins of the pressing members when the auxiliary brackets 128, 130 are in closed position as shown in Fig. 10.

Pivotally mounted on cross bars 104, 104 are pneumatic cylinders 134, 136 having pistons 138, 140 linked to auxiliary brackets 128, 130 and provided with suitable air connections. Slidably mounted in the upper margin of bracket 128 is locking rod 142 carrying locking pins 144, 144 mounted on ears 146, 146 secured to rod 142 by means of a set screw or the like. Brackets 128 terminate in a clevis 148, as shown in Fig. 12, provided with a pair of apertures in alignment with locking pin 144 and mating with an aperture in the margin of brackets 130. A stop 162 is secured to bracket 130 in a position to engage the end of clevis 148 of bracket 130 to position aperture 150in mating relation to the apertures in clevis .148. Mounted on .pedestals 152, 152 at opposite ends of main frame 100, as seen in Fig. 9, is a pair of pneumatic cylinders .154, 156 provided with push rods 158, 160 in alignment with the'ends of locking bar 142.

In operation of the device, the two auxiliary brackets .128, 130 are swung outwardly to open position, as shown in Fig. .11, by means of pneumatic cylinders 134, 136 and all three pressing segments .114, 114 are moved to retracted-position by releasing the air pressure within bladders .118 and permitting springs 124, 124 to compress the bladder. A length of wet fibrous tubing 44 mounted on .imperforate mandrel 46 is then laid on supporting members 126, 126 and cylinders .134, 136 are actuated to urge brackets 128, 130 to locking position,

.as shownin Fig. 10, causing the edge of supporting member 1132 to be forced slightly into the surface of the wet fibrous tubing along with the'edges of supporting members 126, 126.

Cylinder 156 is then .actuated to urge push rod 160 against the end of locking rod 142, causing locking pins 144, 144 to enter their respective clevises 148, 148 and lock the brackets 128, 130 together. Compressed air is then supplied to bladders 118, 118 from any suitable source of air under pressure, causing pressing segments 114, 114 to be urged toward mandrel 46. It will be noted that in this embodiment, the lateral margins of pressing faces 122 are in sliding engagement with the converging faces of supporting members 126, 126, 132, thus elminating the necessity for employing the strip of screen wire 80, 82 to bridge the gap between adjacent pressing members as shown in Fig. 8. When all three pressing segments are fully extended, the adjacent margins of arcuate pressing faces 122 are in mating engagement along the forward edges of supporting members 126, 132. The water which is expressed from the wet fibrous tubing during the pressing operation may be drained from the pressing members 122 .in the same manner as in the embodiment shown in Figs. 1 to 8.

Upon completion of the pressing operation, pneumatic cylinder 154 is actuated to unlock brackets 128, 130. Then cylinders 134, 136 are actuated to swing bracket members 128, 130 outwardly to open position again, permitting the compressed tube to be removed along with its supporting mandrel.

It has been found that best results are obtained by employing-a pressure of about 35 -to 42 pounds per square inch on the fibrous tubing for a time as short as 15 seconds, resulting in the removal of from 1S%-25% by 5 tion absorbed much less pitch in the subsequent impregnation step.

Although specific embodiments of the invention have been described herein, it is not intended to limit the invention solely thereto, but to include all of the obvious variations and modifications within the spirit and scope of the appended claims.

I claim:

1. Apparatus for pressing and compacting wet fibrous tubing upon a cylindrical imperforate forming mandrel, said apparatus comprising three mating pressing segments, each segment having a hollow body portion and a perforate inner face, said segments when in mating engagement forming a hollow cylinder concentric with said mandrel and spaced therefrom by a distance approximately equal to the desired ultimate wall thickness of said tubing, the mating margins of said segments extending substantially parallel to the axis of the mandrel, each segment being individually mounted for movement toward and away from said mandrel along a radial path, hydraulic means for urging each segment toward said mandrel to press and compact said wet fibrous tubing therebetween and express water therefrom through said perforate face into said body portion, spring means for withdrawing each segment from said mandrel when said hydraulic pressure is released, and means for withdrawing said water from said body portion.

2. Apparatus as defined in claim 1 in which'all of the inner faces of said segments are approximately equal in area, individual hydraulic means are provided for each said segment, and a common source is provided for supplying hydraulic fluid under pressure to each said hydraulic means.

3. Apparatus for pressing and compacting wet fibrous tubing upon an irnperforate cylindrical mandrel, said apparatus comprising a main frame, a subframe pivotally mounted on said main frame for swinging movement to and from an open position and a position closed about said mandrel, at least three mating pressing segments, at least one of said segments being mounted on the main frame and at least one being mounted on said subframe, said segments being mounted for movement along radially divergent paths when said subframe is in closed position, said segments having concave perforate inner faces which when in mating engagement at their inward extent of travel together form a hollow cylinder having a diameter approximately equal to the desired ultimate external diameter of said tubing, and fluid pressure means for urging said segments radially inwardly toward their mating position to press and compact said wet fibrous tubing between said segments and said mandrel and to express water therefrom through said perforate inner faces.

References Cited in the file of this patent UNITED STATES PATENTS 329,043 Hotchkiss Oct. 27, 1885 623,808 McAlpine Apr. 25, 1899 658,851 Keyes Oct. 2, 1900 668,943 Westervelt Feb. 26, 1901 1,249,088 Hodge et al. Dec. 4, 1917 1,271,211 Parker July 2, 1918 1,983,553 Manson Dec. 11, 1934 

